A281338 - OEIS

A281338

Number of n X 2 0..1 arrays with no element equal to more than three of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

2, 8, 25, 85, 286, 969, 3281, 11114, 37649, 127541, 432062, 1463673, 4958409, 16797346, 56903505, 192769085, 653033942, 2212249593, 7494324497, 25388138778, 86006095793, 291358440197, 987020046574, 3343677195961, 11327203768153

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OFFSET

1,1

COMMENTS

Column 2 of A281344.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) + a(n-2) + 2*a(n-3) - 2*a(n-4) - 4*a(n-5).

Empirical g.f.: x*(2 + 2*x - x^2 - 2*x^3 - 6*x^4) / (1 - 3*x - x^2 - 2*x^3 + 2*x^4 + 4*x^5). - Colin Barker, Feb 21 2018

EXAMPLE

Some solutions for n=4: